Electric heater construction



Nov. 3, 1964 A. GREENHAUS ELECTRIC HEATER CONSTRUCTION 3 Sheets-Sheet 1Filed Nov. 9, 1961 Nov. 3, 1964 A. GREENHAUS 3,155,812

ELECTRIC HEATER CONSTRUCTION Filed NOV. 9, 1961 3 Sheets-Sheet 2 INVENTOR A: zserrsavww I ATTOR Nov. 3, 1964 A. GREENHAUS- 3,155,812

ELECTRIC HEATER CONSTRUCTION Filed Nov. 9, 1961 m 3 Sheets-Sheet 3 W/Wlll United States Patent 3,155,812 ELEQITRHC HEATER CONSTR'UtZTlGNAlbert Greenhaus, Fresh li leadows, N.Y., assignor to Berke ElectricManufacturing Corporation, Jamaica, N.Y., a corporation of New YorkFiled Nov. 9, 1961, Ser. No. 151,599 8 Claims. (Cl. 219345) Thisinvention relates to an electric heater and more specifically to a noveland improved heater and support for the heating element.

In the design and construction of electric heaters and particularlyheaters embodying plate-like heating elements such as conductive grassand the like it is important that the element be completely insulatedfrom the heater frame and supported in such a manner that it can expand,contract and even warp slightly without placing undue stress and strainon the element. This is particularly important in the case of conductiveglass panel heaters which also require pressure-type electrical contactsfor applying electric power to the panel.

This invention overcomes many of the diificulties heretofore encounteredin panel type heaters and provides an improved heater construction and anew heating element support that are characterized by their simplicity,relatively low cost, durability and ease of maintenance.

Another object of the invention resides in the provision of a new andimproved heater that greatly simplifies the assembly of the componentsincluding a heater sub-assembly and an outer frame structure forreceiving the sub-assembly.

Still another object of the invention resides in the provision of animproved structure for supporting the heater panel in insulatingrelationship to associated metal structures and in the case of heaterpanels, such as conductive glass, for providing pressure electricalcontact with the panel.

A still further object of the invention resides in the provision of anovel and improved end channel for panel type heater sub-assemblies tosupport the heater panel and provide electrical contact therewith.

The above and other objects and advantages of the invention will becomemore apparent from the following description and accompanying drawingsfonning part of this application.

In the drawings:

FIG. 1 is a perspective view of a heater in accordance with theinvention;

FIG. 2 is an exploded view of a fragmentary part of the heatersub-assembly showing the cooperation of the heating panel, end channel,reflector and electrical contactors;

FIG. 3 is an exploded perspective view or" portions of the heater frameand sub-assembly;

FIG. 4 is a perspective view of a fragmentary portion of a glass heaterpanel;

FIG. 5 is an enlarged front elevation of the heater of FIG. 1 withportions broken away;

FIG. 6 is a cross-sectional view of FIG. 5 taken along the line 6-6thereof.

The illustrated embodiment of the heater utilizes a conductive glasspanel having a uniform conductive coating on one side thereof and silvercontacting strips on opposing edges. It is understood, however, that theinvention is equally useful for other types of panels.

Referring now to the drawings, the heater is generally denoted by thenumeral 18 and includes an outer'frarne 11, end portions 12 and 13, agrill 1d and an inner heater sub-assembly generally denoted by thenumeral 15 and comprising a pair of end channels 16, a conductive glassplate 17, contacting members 18 and a reflector 19. The subassembly is aseparate unit which may be readily installed in and removed from theouter frame 11. It is also evident that two or more heaters may beplaced in end to end relationship in which case a connecting membermechanically joining the meeting ends of the two heaters may be utilizedto form, in effect, a single unit of extended length. Moreover theheaters may be of any desired size and wattage ratings.

As pointed out above the sub-assembly forms a separate structuralelement that may be completely assembled and then installed in the frame11. In the installation of this heater, the sub-assembly is normallyremoved from the frame, and the latter is then secured to a supportingsurface and the electrical cable installed. The sub-assembly is thenconnected to the cable and then secured in the housing or frame.

More specifically and with reference to FIGS. 2 and 3, the sub-assemblyincludes a channel-shaped reflector 19 which has a length substantiallyequivalent to the length of the frame 11. The upper leg or wall 2% ofthe re flector 19 is somewhat deeper than the lower Wall 21 and both thewalls have their end portions folded back on themselves in order toprovide an adequate degree of stiffening. The inside surfaces of thereflector 19 are preferably polished in order to reflect the heatgenerated by the panel 17 outwardly from the heater. The rear wall 22 ofthe reflector 19 is provided with a pair of openings 23 and 24 at eachend thereof to receive the legs of the end panels 16 as will bedescribed. The upper and lower walls 29 and 21 of the reflector 19 haveopenings 25 near the ends thereof for attachment of the end channels 16.

The heater channel 16 in the instant embodiment of the inventioncomprises a glass plate 26 having a conductive coating 27 on the backside thereof. The ends of the glass panel 26 are each provided with alow resistance conductive strip 23 of silver or other suitable lowresistance material which forms an electrical contact 7 with theconductive surface 27 so that energy applied to the two conductivestrips 28 will cause the conductive surface 27 and consequently thepanel 26 to be heated.

The panel 17 is mounted in the reflector 19 by means of a pair of endchannels 16. These end channels are preferably formed of a suitableinsulating material capable of withstanding the temperatures of thepanel. While any suitable material may be utilized for this purpose, aphenolic resin containing asbestos has been found useful for lowtemperature heaters. For high temperature heaters it is apparent thatother insulating materials such as ceramics or the like may be employed.

Each end channel 16 comprises an essentially rectan gular body 29 havingrounded lower or inner corner portions 3d to conform with theconfiguration of the reflector 19. In addition the body is provided witha pair of legs 31 and 32 which have a Width approximately half the widthof the body 29. When each channel is mounted in the reflector the legs31 and 32 extend through the openings Z3 and 24 in the reflector and thechannel is secured in place by a pair of screws 33 which extend throughthe cooperating openings 25 in the reflector and threadably engageopenings 34 in each end wall of the channel.

As will be observed in the drawings each channel is essentially hollowand includes partitioning members to receive and hold the contactstructure 18 and the end of the heating panel 17 containing theconductive strip 28. A heating panel receiving and supportingcompartment is formed within each end chanel by a pair of inwardlyextended coplanar partitioning elements or members 35 and 36 which areparallel with the top or outer wall 37 and the bottom or inner Wall 33.These partitions form an elongated slot 3) having a width slightlygreater than the thickness of the panel 17 and a length slightly greaterthan the width of the panel 17. In this Way slight distorp 57 of theframe.

tions of the panel in heating and cooling will not unduly stress thepanel and cause it to fracture. The contact structure 13 is arranged tobe received by and held within the end channel 16, and for this purposethe structure includes a flat strip 46* of conductive material and abowed spring 41 carrying carbon button contacts 42 on the outer endsthereof. The center of the spring 41 is secured to the strip by rivets43 or other suitable fastening means. One end of the strip at) is fittedwith a connector 44 and a lead Wire 45 is secured to the connector 44.

Retention of the contact structure 18 within the panel 16 is effected bythe provision of suitable partitions and stops within the body. Morespecifically, the partition 36 includes an end wall d6 extending to thewall 38 and having a cutout 47 therein. The cutout has a widthapproximately equal to the width of the strip 4%} and a height somewhatgreater than the thickness of the strip 4t}. A spacing member 48 iscarried by the wall 38 and has its outer edge aligned with one edge ofthe opening 4'7. A stop 49 is disposed between the wall 46 and theadjoining end wall of the body 2), and limits longitudinal movement ofthe strip itl when placed within the channel 16. 6n the other end of thechannel it? there is an L-shaped wali having legs 4% and 54 with the legor stop 49' extending to the outside wall 51 of the body 29. The leg 54)is generally coincident with the inner edge of the wall 38. An innerspacing member 52 which is seen more clearly in FIG. 6 extends from thepartition 35 to the wall 33. The wall 51 of the body 29 includes anopening which is substantially in alignment with the wall 543- for thereception of the lead wire 4:") fastened to the contact structure 13.When the contact structure 18 is in place within the end channel 16 asshown in FIGS. 3 and 6 it is maintained in position by the spacingmembers 425 and 52, the cutout 47, the wall part and the laterallyspaced stops 49 and 49. The heating panel is inserted in the channel andthe contact buttons 42 will be aligned with and press firmly against theconductive strip 28 to make contact with the panel. At the same time,the pressure of the contacts against the panel securely locks thecontact structure 18 in place within the channel.

Upon attachment of the channels 16 to the ends of the heating plate 17the assembly is then placed in the reflector 119 with the legs 31 and 32extending through the cooperating openings. Screws 33 are then insertedthrough openings 25 and tightened into cooperating openings in the endchannels 15 to complete the fabrication of the sub-assembly. The leadwire which in the instant embodiment of the invention would have alength of two to three feet is then threaded through an opening 53 inthe leg 31 which now directs the wire toward the center of thesubassembly and causes it to lie 011 the back side of the reflector 19.The sub-assembly 15 further includes a pair of spring clips 54 as shownin PlGS. 3 and 6 each of which has a rounded back portion 55 which liesagainst the reflector and an opening to receive the upper screw 33 whichholds the clip in place. The forward flanged end portion 56 cooperateswith a portion of the frame 11 as will be described to hold thesub-assembly lid in place in the frame.

The heater frame Ell comprises an elongated back wall 57, a top wall 53,and a bottom wall 59. The bottom wall further includes a'verticallyextending front portion or wall the top edge of which is bent inwardlyto form a compound flange comprising sections 63 and 62. The flangedportion 62 is dropped below the flange portion 6?. to form a shoulder63. The top-wall dsincludes a front edge portion having a verticallydisposed wall section a horizontally disposed wall section Q35 and areversely formed end portion comprising downwardly and inwardly inclinedpart as and an inwardly extending portion 67'.

The forwardmost wall portion es of the frame 11 extends beyond from thebottom front wall so that when the 4 grill lid is in place, it isinclined relative to the rear wall trical contact structuretherebet-ween, and laterally spaced The rear wall 57 of the frameincludes a pair of tabs 68 and each end of the frame which extendinwardly and cooperate with the upper legs 31 of the channels 16 whenthe sub-assembly is positioned in the frame. In addition, the lip orflange 62 includes a pair of cutouts $9 at each end thereof toaccommodate the lower screws 33 on the subassembly structure.

With the invention as described and with the sub-assembly assembled asshown in FIG. 3, the latter is ready to be inserted in the frame 11. Toaccomplish this the lower edge 21 of the reflector is moved intoengagement with the lip 62 on the lower portion of the frame. Thesub-assembly at this point is inclined outwardly from the frame. Thesub-assembly is then moved completely into the frame by pivoting itabout the lower edge of the reflector, and in so doing, the legs 31 and-32 will move backwardly until they lie flush against the back wall 57of the frame. At this point, the legs 31 of the channels 16 will liebeneath the tabs 68 as will be observed in FIG. 6. The springs 54 duringthis operation are held in a depressed position to clear the front edgeportions 66 and 67 of the top wall 53. When the sub-assembly is properlypositioned within. the frame the springs 54 are released and rideupwardly behind the inwardly extending frame edge 67. The springs holdthe sub-assembly tight against the rear wall 5'7 of the frame and thetabs Gil prevent the sub-assembly from being shifted upwardly. Inaddition, the front edge of the lower wall 21 of the reflector buttsagainst the shoulder 63 011 the frame and the lip or flange 62 providesthe support for the subassembly.

The frame 11 may include a number of electrical knockouts for thereception of suitable electric cable connectors, as for instance theconnector 7%. The supply c nductors 71 brought in through the connector7% are attached to the leads 45 to supply energy to the heater. Thegrill 14 is held in place by upper openings 72 in the upper wall portion67 and lower openings 73 in the flange portion 61 of the lower framepart.

After assembly of the heater as described, the end members 12, 13 areplaced in position as illustrated and secured to the frame .by screws74. As previously described heaters of the type described above may beconnected in and to end relationship by appropriate coupling memberswhich join the heaters one to the other and form a substantially unitarystructure.

While only one embodiment of the invention has been illustrated anddescribed, it is evident that alterations, modifications and changes maybe made without departing from the true scope and spirit thereof.

What is claimed is: 1

l. in an electric heater, a sub-assembly comprising a reflector, anelectric heater panel having terminal means for the application ofenergy thereto, and channels of insulating material having openingstherein for receiving opposing ends of said heater panel, said terminalmeans comprising electric contact strips on said opposing ends of saidpanel, spring loaded electric contact means in each of said channels,said contact means engaging said contact strips and means on saidchannels for securing said panel to said reflector and retain thechannels in engagement with the heater panel, each of said end channelscomprising an elongated hollow structure having end walls, top andbottom walls and one side wall, at least one partition between the topand bottom walls to form an elongated panel receiving channel, and'meanson said bottom wall receiving and retaining said electrical contactmeans.

2. An insulated end channel for an electric heater comprising anelongated hollow body having end walls, top and bottom walls and oneside wall, a pair of spaced coplanar elements between the top and bottomwalls to form an elongated opening for reception of a heater panelbe:tween the elements and said top wall, ,a pair of spaced stops on'saidbottom wall for receiving an elongated elecstops on said body tomaintain said contact structure in predetermined lateral alignmentwithin said end channel.

3. An insulated end channel according to claim 2 wherein said bodyincludes at least two legs on said bottom wall and extending outwardlytherefrom in spaced parallel relationship.

4. An electrical heater comprising a frame having a back wall, a topwall and a bottom wall, with the latter having its forward portion bentupwardly and inwardly to form a bottom channel and an inwardly extendingledge, a subassembly including -a reflector having a rear wall and topand bottom walls, an electric heater panel between the top and bottomreflector walls and spaced from the rear reflector wall, said heaterpanel having terminal means on opposing ends thereof, a pair ofelongated end members of insulating material secured to said reflectorand engaging ends of said heater panel, electrical contacts carriedwithin said end members and electrically contacting said terminal means,spacer means extending from said rear reflector wall, said bottomreflector wall resting on said ledge with the spacer means engaging saidback frame wall and means carried by said reflector and releasablyengaging said frame to hold the sub-assembly therein.

5. An electrical heater comprising a frame having a back wall, a topwall and a bottom wall, with the latter having its forward portion bentupwardly and inwardly to form a bottom channel and an inwardly extendingledge, a sub-assernbly including a reflector having a rear wall and topand bottom walls, .a heater panel between the top and bottom reflectorwalls and spaced from the rear reflector wall, end members of insulatingmaterial secured to said reflector and engaging ends of said heaterpanel, spacer means extending from said rear reflector wall, said bottomreflector wall resting on said ledge with the spacer means engaging saidback frame wall and means carried by said reflector and releasablyengaging said frame to hold the subassembly therein, said spacer meansform part of said end members and said rear reflector wall includesopenings through which said spacer means extend.

6. An electric heater according to claim 4 wherein said back frame wallincludes stops extending inwardly thereof and overlying at least certainof said spacer means to restrict upward movement of said sub-assemblyrelative t said frame.

7. An electric heater according to claim 4 wherein said releasable meansincludes spring means extending in a forward direction of and engagingthe top reflector wall and said top frame wall includes meanscooperating with said spring means for holding said sub-assembly in saidframe.

8. In an electric heater, a pair of insulated channels positioned inspaced relationship, each of said channels comprising an elongatedstructure of insulating material having at least two elongated openingsin one side thereof, an electrical heating panel including terminalmeans on opposing ends thereof, each of said opposing ends of said panelextending into one of said openings in one of said elongated structures,spring loaded electric contact means in the other opening in each ofsaid elongated structures and electrically contacting the terminal meanson the associated end of said heating panel and means for retaining saidheater panel and said elongated structures in engagement one with theother.

References Cited in the file of this patent UNITED STATES PATENTS2,706,763 Glynn Apr. 19, 1955 2,781,440 Petersen et a1 Feb. 12, 19572,795,682 Knoll June, 11, 1957 2,845,527 MoEachron July 29, 19582,858,515 Thunander et al Oct. 28, 1958 2,911,6l2 Jackson et al. Nov. 3,1959 2,995,644 Zellers Aug. -8, 1961 3,015,083 Juris Dec. 26, 196-13,026,398 Quirk Mar. 20, 1962

1. IN AN ELECTRIC HEATER, A SUBASSEMBLY COMPRISING A REFLECTOR, ANELECTRIC HEATER PANEL HAVING TERMINAL MEANS FOR THE APPLICATION OFENERGY THERETO, AND CHANNELS OF INSULATING MATERIAL HAVING OPENINGSTHEREIN FOR RECEIVING OPPOSING ENDS OF SAID HEATER PANEL, SAID TERMINALMEANS COMPRISING ELECTRIC CONTACT STRIPS ON SAID OPPOSING ENDS OF SAIDPANEL, SPRING LOADED ELECTRIC CONTACT MEANS IN EACH OF SAID CHANNELS,SAID CONTACT MEANS ENGAGING SAID CONTACT STRIPS AND MEANS ON SAIDCHANNELS FOR SECURING SAID PANEL TO SAID REFLECTOR AND RETAIN THECHANNELS IN ENGAGEMENT WITH THE HEATER PANEL, EACH OF SAID END CHANNELSCOMPRISING AN ELONGATED HOLLOW STRUCTURE HAVING END WALLS, TOP ANDBOTTOM WALLS AND ONE SIDE WALL, AT LEAST ONE PARTITION BETWEEN THE TOPAND BOTTOM WALLS TO FORM AN ELONGATED PANEL RECEIVING CHANNEL, AND MEANSON SAID BOTTOM WALL RECEIVING AND RETAINING SAID ELECTRICAL CONTACTMEANS.